1. Field of the Invention
The present invention relates to a method and apparatus for signal processing.
2. Description of Related Art
Techniques for performing image processing such as edge enhancement and blurring using a convolution filter such as a Laplacian filter or Gaussian filter are known from the past (see, for example, JP-A-2009-79949).
However, related art techniques do not have any filter that acts precisely on any arbitrary input image. Consequently, it has been required to use a filter whose parameters have been adjusted by assuming input images. Furthermore, a wavelet algorithm that expands an input image into image elements of plural resolutions is known. The input image is expanded into a series of image elements which are half as many as there are pixels. Therefore, the resolutions differ greatly. This presents the problem that it is impossible to finely adjust the image quality. Another problem with wavelet analysis is that an exorbitantly long time is required to process a large image because the input image is expanded.